Not sure where you are getting the link for it but the app can be found here
https://www.dji.com/uk/goapp
Use apkmirror website to get an older version of the app, you may have to try a few to find one that works
Looking at the RC2 specifications, the only reason that it would need connection to a phone would be to give it internet connection. Disabling mobile data (not near a wifi connection) would sever that.